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I have a problem with the front brakes on my 1926 333 Packard. If they are adjusted so that there is the required amount of drag etc and then the front wheels are turned to the right the right wheel brake applies enough brake to make it too hard to turn the wheel by hand. If the wheel is returned to the centre or straight ahead position the brake is released. The same happens to the left wheel when the wheels are turned to the left. It appears as though the cam moves when the steering is operated but I wonder if this is inherent or is there a trick to overcome the problem.

Having driven several 2nd and 3rd series Packards with the 3-shoe Perot brake system I can assure you that what you're experiencing is NOT inherent to the system. This topic has come up at least once before on this forum so perhaps if you use the search tool you'll find it, or someone else may steer you to it.

Also have you read thru and followed the factory adjustment regime? It's on this site atpackardinfo.com/xoops/html/downloads/1929_BendixBrakesServiceBulletin.pdf


Sorry I can't help with specifics but please keep us informed as you work thru the problem.

Hey Phil:

Sounds like something is sticking.

First divide the system by disconnecting the front brake cables at the clevis pins. If the problem persists look for binding pivots and cables sticking where they pass through the chassis behind the front wheels. Remove the cover plates and check for hardened grease at that point.

If the problem is not present with the cables disconnected check for binding equalizer bars.

The wheels should spin free with no brake drag. If there is drag it should be eliminated.

The chassis lubricator should be working and the front brake actuators should be getting oil. If not, the sticking problem may be due to lack of oil. If fixing the lubricator is beyond your interests an oil can may help.

The actuator pivots on the frame are sometimes put together wrong and the binding will cause problems due to toe out on turns. The inner wheel turns sharper than the outside wheel and that extra motion has to go somewhere.

Phil,
This problem is described in the attached article on Bendix brakes.
David

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Thanks David for the link.
The brakes there have a different actuator arm than the perrot style "universal" that is on my car.
I think the principle is still the same that there needs to be a certain distance from the centre line of the kingpin to the pivot/cam centre. I am not sure how to achieve that with this style of brake.
The cause seems to be in the hinge action of the universal that causes the cam to turn slightly with the steering action. Even with biasing the cam back slightly on the splines it would still get adjusted out when the cable is adjusted for the correct shoe clearances. Still wondering!

I have added a couple of shots for clarity. The cam does not move when the hub is turned left but moves when turned right. It's only a small amount but it still applies significant brake.Moving the cam carrier bracket has no effect. It appears to be the alignment of the brake shaft from the chassis to the wheel that is the problem. I don't have another similar vehicle to compare it with. I could probably live with the condition but it would be great to have a solution.
(Yes I have some modern shock absorbers fitted until the snubbers are restored.)

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Phil,

Recently listed on Aussie eBay is this '20's Brake Manual

Phil,

Nothing to do with your brake binding problems but that universal joint on the actuator shaft is very exposed which will result in wear due dirt and water ingress
New reproduction cover kits are available for Max Merritt. They are well worth fitting.

parts123.com/parts123/yb.dll?parta~dyndetail~Z5Z5Z50000022a~Z5Z5Z500484~P60.00~~~~S4I107WOXA10119120150G~Z5Z5Z5~Z5Z5Z50000022A

Those universal joints can suffer extreme wear to the point of coming apart, I wonder if your problems are related to excessive wear. Are they heavily worn?

David

Thanks Mal, I have bought the book off E bay. Hopefully it will be useful.
David - the brake linkages are all in good order. I had to get some parts remade. The dust covers were bought from the states and when the retaining spring is released there is a brass cover under the outer steel cover. This looks strange in the photo but it has a layer of grease on it.

Strangely since I have had the hubs off and checked the brakes the car has started to shudder if some uneven road surface is encountered.

It excites a resonance that is only stopped by slowing down. There was some previous shudder but not as severe.
It was so bad that one of the bonnet clips broke off and was lost!

There is a small amount of play in the steering box that needs to be adjusted out, as well as ensuring the wheel bearing clearance is correct.

I checked the toe in and it is about 1/8". The book says that is the right amount with "balloon" tyres.

Would it be sufficient for modern reproduction tyres?

Phil,
Is the shudder you refer to wheel shimmy? I have experienced wheel shimmy with both the 633 and the 126, very occasionally. It has usually happened when hitting a bump,for example on a railway crossing. I had the wheels balanced which seemed to help, it hasn't happened again for a long time. If you google wheel shimmy you will get lots of advice!

I think 1/8" toe in is fine but as you will find the tie rod does not have LH and RH threads so to adjust toe in you need to remove a tie rod end and rotate it through 360 deg either way. Whenever I have done this it results in a little too much or too little toe in. However I don't think its critical. Not one of Packards finer features. Hopefully this feature was corrected on later models?